1. Field of the Invention
The present invention relates to a method of determining the optimum exposure conditions for a photographic color printer and more particularly to an improved method of making it possible to quickly and easily determine the optimum exposure conditions for a photographic color printer to correct difference in characteristics of processed color prints caused due to difference in characteristics of photographic printing paper and photographic color printer, wherein the method is performed by way of the steps of preparing a plurality of test prints under different exposure condition using a standard negative film by way of exposing, developing and drying of printing paper to be used later in photographic color printer to be used later, measuring optical density for each of color components on the test prints, comparing their optical density with that of corresponding color on a standard print, detecting density difference between each of test prints and standard print and then determining corrective value required for correcting the above density difference.
2. Description of the Prior Art
Color sensibility of color printing papers usually varies in dependence of their manufacturers and moreover it varies appreciably among printing papers manufactured by the same manufacturer. Further, it varies also in dependence on the number of days that elapse since their manufacturing as well as in dependence on how they are stored. On the other hand, characteristics of color printing such as characteristics of exposing inherent to a photographic color printer vary in dependence on the kind of photographic color printer to be used because different light source, filter and others are incorporated in the color printer. In view of these variations as mentioned above remedial actions have been hitherto undertaken in the following manner prior to initiating printing operation on printing paper to be used later by operating a photographic color printer to be used later. Namely, test printing is performed on printing paper to be used later under different exposure condition using a standard negative film, processed test print is visually observed by an operator and test printing and observing are repeated until the optimum exposure conditions (normal exposing values) are reached.
Since the conventional method of determining the optimum exposing conditions has been performed by way of so-called try-and-error steps, a number of labor works are consumed and highly trained skill is required for accomplishing the method.